Back in mid June, I had 2 of my bettas in a divided, filtered, heated 10gal. It was uncycled and I did regular water changes. Tried using Stability to cycle the tank with the fish in it. It went well until one of the fish came down with Ick so I removed BOTH fish from the 10gal into seperate bowls with no filtration. They have been there since with very regular water changes and have actually remained very happy.

I was doing water testing a couple of weeks before the Ick started so I assumed that the fish had been in the tank long enough to create some waste and kick the nitrogen cycle into gear (as long as I didn't do any more water changes).

I assumed, with Nitrites being up and Ammonia down, that the cycle was moving along. I did no other testing until today. There have been NO changes made to the tank with the exception of adding conditioned water when a lot of evaporated.

I'm no expert on cycling, but I have done a lot of research, and in order for the cycle to complete it needs a constant source of ammonia to feed the bacteria cultures, to keep the cycle going and get the correct bacteria formed, which means no fish = eventually the cycle stops.

I found it easier (and faster) to kickstart the cycle by using filter media from an already cycled tank...

example - I've been running 2 filters on my 20 gallon tank - when I started my 30 gal tank - I took one filter from the 20 gal - and put it on the 30 gal. within 2 days, my water was testing nitrites/nitrates (and yes ammonia)

I then added the filter I wanted to really use on the 30 gal. tank - (I bought it two days after the tank was set up) - and, right now - a week later, the tank is still running two filters - old plus new. - I tested the water last night - and, the 30 gallon after 1 week of being set up - is now testing as 0 ammonia, 0 Nitrites, 0 Nitrates.

In another month or so, I think that the 'new' filter will be fully seasoned with good bacteria - so then I will be able to remove the old filter from the 30 gallon and use it to 'cycle' any other new tank I will set up...